Add Claude Haiku 5.5 to the Anthropic provider #2208

Summary

Claude Haiku 5.5 is available on the Anthropic API but does not appear in the model list when Anthropic is used as the provider. Sonnet 5 is listed, but Haiku 5.5 is missing — the newest Haiku offered is Claude Haiku 4.5 (claude-haiku-4-5-20251001).

Reported by a user on Discord.

Details

The Anthropic provider's model list is defined in packages/types/src/providers/anthropic.ts (anthropicModels). It currently includes claude-sonnet-5, claude-opus-5, claude-opus-5-5, claude-fable-5, and claude-fable-5-1, but no Haiku 5.5 entry.

Expected behavior

claude-haiku-5-5 (exact API ID to be confirmed against Anthropic's docs) is selectable when Anthropic is the configured provider, with accurate model metadata: max tokens, context window, pricing, image support, prompt-cache support, and the reasoning/sampling conventions of the newer 5.x models.

Notes

• Newer 5.x models (Sonnet 5, Opus 5/5.5, Fable 5/5.1) use adaptive thinking: supportsReasoningBudget: true, supportsReasoningBinary: true, and supportsTemperature: false (manual budget_tokens and sampling params return a 400). Haiku 5.5 should be checked against that convention.
• Check whether src/api/providers/anthropic.ts (the switch (modelId) in the streaming path) needs a case for the new ID.
• Specs/pricing should be sourced from https://docs.anthropic.com/en/docs/about-claude/models and https://platform.claude.com/docs/en/about-claude/pricing.